\ IS 1528 ( Part 19 ) : 1991 Indian Standard (Reaffirmed 2002) METHODS OF SAMPLING AND PHYSICAL TESTS FOR REFRACTORY MATERIALS PART 19 DETERMINATION OF THERMAL EXPANSION UDC 666'76 : 620' 113 0 BIS 1991 BUREAU MANAK OF INDIAN 9 BAHADUR STANDARDS SHAH ZAFAR MARG BHAVAN, NEW DELHI 110002 Price Group 2 September 1991 Refractories Sectional Committee, MTD 15 i FOREWORD 9 This Indian Standard ( Part 19 ) was adopted by the Bureau of Indian Standards, after the draft finalized by the Refractories Sectional Committee had been approved by the Metallurgical Engineering Division Council. : .a. Determination of thermal expansion ( reversible thermal expansion ) wgs given as an appendix to IS 4812 : 1972 `Specification for silica refractories for coke oven'. The technical committee felt that it will be appropriate if a separate standard is published as a part of series of Indian Standards on methods of sampling and physical tests for refractory materials. Assistance has been taken from BS 1902 : Part 1A : 1966 `Methods of testing refractory Sampling and physical tests' in the formulation of this standard. v ; materials - For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 `Rules for rounding off numerical values (revised)`. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. IS 1528 ( Part 19 ) : 1991 Indian Standard METHODS OF SAMPLING AND PHYSICAL TESTS F(R REFRACTORY MATERIALS PART 1 SCOPE 1.1 This standard prescribe ' - methods of test expansion. The for determination of ther. standard covers two method ; 19 DETERMINATION OF THERMAL EXPANSION a) Dial gauge method for temperatures 1 150°C up to NOTE - This method is suitable for occasional measurements up to 1200°C. Repeated heating to 1200°C may produce some decitrification of the fused silica tube and change its expansion characteristics. It is recommended that an apparatus which is frequently used for tests up to 1 200°C should be recalibrated regularly for examplt after every 10 tests. b) Electrical method for temperature 1 150°C and 1 500°C. 2 REFERENCES between 2.1 The following Indian Standards are necessary adjuncts to this standard. IS No. Title Methods of sampling and 1528 (Part 7) : 1974 physical tests for refractory materials : Part 7 Methods of sampling and criteria for conformity Glossary of terms relating to 4041 : 1987 refractory materials 3 TERMINOLOGY 3.1 For the purpose of this , tions given in IS 4041 : 1987 ndard, the defini111apply. end (B) being fixed to the stand ( T). At point (D) in the tube, corresponding to the mid-point of the furnace (F) tube and of the test piece, two holes pierce the top of the tube and through these are threaded the two wires of a platinum `v' platinum rhodium thermocouple. The test piece (not shown ) lies in the tube between the end (A ) and the end of the fused silica rod ( XY). Thus rod just fits in the silica tube (AB) and can move longitudinally without touching the walls, since it is supported from the end ( Y), which is compented into a hole in the iron/36 percent nickel alloy rod ( 2 ). The pulleys PI and Pa (which are mounted on ball bearings) carry the iron/36 percent nickel alloy rod ( Z), which is free to move backwards and forwards with minimum resistance. The iron/36 percent nickel alloy rod transmits the movement of the end of the test piece to a micrometer dial gauge ( G) which is bolted in a slot in the mounting bracket (5'). The micrometer dial gauge is graduated in divisions of 0'01 mm. 4.1.2 Vertical Type 4 DETERMINATION OF T lERMAL EXPANSION BY DIAL GI GE METHOD FOR TEMPERATURE UP 0 115O'C 4.1 Apparatus 4.1.1 Horizontal Type The apparatus to be used is illustrated in Fig. 1. It is mounted on a slate base ( W). The fused silica tube ( AB) is closed at the end (A ) by a ground and polished disk of fused silica, the other The apparatus to be used is illustrated in Fig. 2. It consists of a cylindrical electric furnace of 500 W capacity placed vertically, a fused silica tube closed at one end and centrally suspended within the furnace from top, and a fused silica rod for transmitting the expansion or contraction of the sample. A direct dial gauge of 1'0 cm range with the finest graduation of 0.01 mm is, used for measuring the linear change of the specimen. The furnace top is covered with a metallic plate having a central grooved seat for metallic flange fitted to the open end of the fused silica tube. This arrangement helps in keeping the tube exactly vertical as well as in the centre of the furnace. The block to the dial gauge which accurately fits in the flange on the tube. All these metallic parts are cooled by running water during the test. Thermocouple is inserted in the tube so that the hot junction touches the middle of the test specimen. FIG. 1 HORIZONTAL TYPE THERMAL EXPANSION APPARATUS 1 IS 1528( Part 19 ) : 1991 K- r THERMOCOUPLE TERMINALS FIG. 2 4.2 Calibration DIAL GAUGE APPARATUS FOR THE DETERMINATION ot: REVERSIBLE THERMALEXPANSION the fused silica tube in between the two fused silica discs so that the specimen is not displacced during the test. Place the fused silica rod on the upper fused silica disc on top of this specimen. Introduce a suitable (for example, platinum/platnium-10 percent rhodium), thermocouple within the tube so that its hot junction is almost at the centre of the specimen. Place carefully the metallic block into the metallic flange on the fused silica tube so that its hot junction is almost at the centre of the specimen, tube, discs, rod, etc, is absolutely free in movement. Put this assembly on the cover plate of the furnace and set the dial gauge under slight compression on the metallic block for recording the expansion or contraction. Start heating the furnace and control the rate of heating at 3 to 4°C per minute. The thermocouple shall be connected to a temperature recording device. The temperature along with the reading of the dial gauge shall be noted every 5 minutes. 4.5 Report of the Results The dial gauge reading at 1 OOO'C corrected according to calibration data gives linear change for the sample and shall be expressed as percentage of the original length of the specimen. If necessary a graph relating to expansion and temperature may also be ploted. 2 To allow for any temperature variation between the outside silica tube and the specimen and for the expansion of the length of fused silica tube surrounding the silica tube the appratus shall first be calibrated. With a 50 mm test piece of fused silica, a calibration test shall be carried out at the standard rate of heating to 1 000°C and any deviation from the zero reading on the dial gauge shall be noted. The expansion figures obtained in all subsequent tests with the apparatus shall be corrected by addition of the difference between the dial reading at a given temperature during the calibration test and the true expansion of 50 mm test piece of fused silica at that temperature. 4.3 Test Specimen The test specimen shall be 50 mm in length and 10 mm in diameter and shall be obtained from the sample either by core drilling, or by cutting and grinding. 4.4 Test Procedure Measure the length of the test specimen accurately by slide callipers. Place the test s`pecimen inside IS 1528 ( Part 19 ) : 1991 5 DETERMINATION OF THERMAL EXPANSION BY ELECTRICAL METHOD FOR TEMPERATURES UP TO 1150°C AND 1 500°C 5.1 Apparatus 5.1.1 It consists of suitable furnace with a heating chamber 125 mm by 100 mm fitted with a removable lid and heated by six heating rods 11 mm in diameter arranged around the test piece as shown in Fig. 3A and 3B. Two holer ( approx 12 mm in diameter ) are drilled through one wall of the furnace to accommodate the specimen carrier arms. These arm are 50 cm long one is fixed and the other pivoted at its mid point by a crossed strip I TEST PIECE / TROUGHS FOR COOLING i WATER -4 CROSS-STRIP HINGE + SPRINGS & THERMOCOUPLE IRON/36 PERCENT NJCKEL ALLOY..j'LATE MICROMETER 3A c'""""`""`-" I 1 I Plan of Apparatus i r TEST PIECE THERMOCOUPLE 0 `TEST PIECE 3B Arrangement of Heaters THERMALEXPANSIONAPPARATUS ( ELECTRICAL MEASUREMENT ) FIG. 3 3 IS 1528 ( Part 19 ) : 1991 The specimen is held between the ends of two horizontal arms, one of which is fixed and the other pivoted at its mid-point when the specimen expands the other end of the arms are closed together by a similar distance. A linear transducer is mounted on the ends of the arms opposite to the test piece. The transducer shall have the following characteristics: a) Stable over the required conditions of the test. c) Exert no detectable moving arm. period under the b) Able to detect a movement of 0'000 2 cm constraint on the the top of the furnace into the jaws so that the small projection on each jaw is on the vertical centre line of each end face of the specimen. The furnace lid is replaced and the calibration of the transducer checked by means of a micrometer which is permanently attached thereto (see Fig. 2). The test piece shall be heated at a steady rate and the between S"C/min and lO"C/min readings of the temperature and the change in in length of the test piece, as shown by the transducer, are recorded at 5 :minute intervals or as required. The expansions of the alumina arms, which is at right angles' td the direction of measurement of the specimen, will have a negligible effect on the result. 5 4 Report of Result ' d) Give a final d. c. voltage, proportional to the movement of the arm, which can be indicated or recorded on a transducer. 5.2 Test Specimen The test piece shall be cut or ground and shall be either a prism 5 cm long and 1 cm square or a cyhnder 5 cm long and 1 cm in diameter. The two ends shall be flat and parallel to each other. 5.3 Test Procedure The measured expansion shall be calculated as percentage of the original length of the specimen. If necessary, a graph relating to expansion and temperature may also be plotted. 6 SAMPLING CONFORMITY 6.1 The procedure for sampling and the criteria for conformity shall be as laid down in IS 1528 (Part 7) : 1974. AND CRITERIA FOR The length of the test piece shall be accurately measured and it shall then be inserted through 4 Standard Mark The use of the Standard Mark is governed by the provisions of the Bureau of Zndian The Standard Mark on Standards Act, 1986 and the Rules and Regulations made thereunder. products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well defined system of inspection, testing and quality control which is devised and supervised by BIS and operated by tho producer. Standard marked products are also continuously checked by BIS for conformity Details of conditions under which a licence for the to that standard as a further safeguard. use of the Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards. 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